This is a 80mm f/5.6 lens in a Schneider Electronic Shutter.Lenses designed for infinity lose sharpness and distort when applied to higher magnifications approaching 1:4 (or higher). The Macro Apo-Digitar lenses have been optimized for a ¡:¡ reproduction ration, with excellent performance in the 1:4 to 4:1 range. This allows image quality at or beyond the limit of the performance of current high-resolution chip backs.